AES E-Library

Decoding historic mechanical recordings using noncontact optical methods avoids further degradation that would be created with a stylus. Moreover, for recordings that have been damaged, contact methods do not work. The proposed method, which is based on surface metrology of engineering surfaces, measures the surface optically, while offline signal processing then recovers the audio information. The surface record, preserved as a high-resolution matrix grid, is retained indefinitely. Preliminary results indicate better noise and distortion performance compared to mechanical playback.